Pagoda Urethane Bushings in Stock

[roymil]

Hello, I just received my new bushings from Miller's, along with a cool hat.   

Does anyone have an idea about how much we should torque the sway bar bolts when installing these new urethane bushings?   I had put in some of the regular rubber ones a couple years ago and remember one split as I was tightening the nut down, probably too tight, but I don't want to make that mistake again and I couldn't find a spec for proper torque so I'm hoping someone knows. 

thanks again to Wallace and Millers for making these available.   -Mark

[dirkbalter]

Hello, I just received my new bushings from Miller's, along with a cool hat.   

Does anyone have an idea about how much we should torque the sway bar bolts when installing these new urethane bushings?   I had put in some of the regular rubber ones a couple years ago and remember one split as I was tightening the nut down, probably too tight, but I don't want to make that mistake again and I couldn't find a spec for proper torque so I'm hoping someone knows. 

thanks again to Wallace and Millers for making these available.   -Mark

Mark,
I believe you are asking about the M14 nuts.
These should be 12 kpm or 120 Nm (BBB)

[wwheeler]

We are taking about the bushings on the end links? There are four per side and are on the long 8mm bolt.

[dirkbalter]

We are taking about the bushings on the end links? There are four per side and are on the long 8mm bolt.

If that’s the case, I misunderstood. I don’t think the manual has torque settings for these. A regular M8 (8.8 ) bolt is typically 23-25 Nm. I did these a while ago and don’t recall any issues tightening them.

[roymil]

Yes, I was asking about how tight to torque the nuts on the long 8mm bolts that anchor the ends of the sway bars.   I assume the urethane bushings can handle much more pressure than the original, very spongy rubber, so I was assuming it would be a good thing to make them tighter than original spec for the highest possible stiffness.  I just have no idea how much more pressure the urethane can handle and I also don't want to go so tight that I risk twisting the bolt off or splitting the bushing, as I did once before.  Also I'm thinking it might make sense to go up to a higher grade bolt too since that looks like the weakest link in the whole assembly.   

[wwheeler]

Looking at a generic torque chart, a 8mm bolt wit 8.8 hardness should take a max torque of 28NM or 18 to 20 Ft. lbs. That jives with what Drikbalter shows on his list for an 8mm bolt with 2.5 KPM.

That being said, you will not deform the urethane at that torque setting. Because the urethane does not give like rubber, there is more stress on the bolt during operation and would be an upgrade to increase the hardness a notch. I would stay with what is the recommended torque for that size of bolt. The amount torque is not going to effect the handling. You just want to make sure it is secure and not get loose.

I hope that helps.   

[wwheeler]

I was talking to a friend who is an expert with these cars. He says that if the bolt and hardware is original, you should tighten the assembly until the nut bottoms out on the threads. Another thought is that you would only tighten the end link bushings until they expand to the same diameter as the cup washers. Never more than that. You can also use the max torque value for an 8mm bolt as another limit.

Using the three guides above when tightening the end link bushings, I think you will get it where it needs to be. Again, I don’t think this is critical issue, it just needs to be secure.

If the rubber end link bushings were compressed to the point of cracking, I suspect that maybe the bolt was not the original threaded dimensions. And also the bushings could have been compressed so that they were larger in diameter than the cup washers.

Let me know.

[wwheeler]

FYI, for those Pagoda owners that also have 190SLs, I have suspension bushings for the 190SLs as well as other Pontons. These are recent additions. Send me a PM and I can send you more info.

Wallace

[JamesL]

OK...
Anyone gone live with these and got any feedback? My car improved immeasurably when the old rubbers were replaced with new (stock) but I'm interested in any feedback on the urethane.

[wwheeler]

Feedback is indeed hard to get. I know that several sets have been sold to this group. Not sure if they have been installed yet.

These tools have been around since 1995 and Cox Racing sold hundreds of sets since. I am using basically the same compound although just a bit softer. My parts match up dimensionally the same as what Cox racing produced. In addition to W113 cars, Cox sold sets for W112 and 6.3 W109 cars. Many were also sold to modified W108 cars that were looking for much improved handling. I know a local shop that works on mostly SL models (W121 190SL and W113) and has installed many sets from Cox over these years. In fact, that shop is the reason I bought these tools recently and expanded the line to the 190SL. They loved the urethane on these cars.

I wrote a document that basically explains the difference between urethane and OEM rubber (see attached). Urethane won't be for everybody and I acknowledge that. Last thing I want to do is have these parts installed on a car where the owner is dissatisfied and just wanted to refresh the OEM parts.     

[mazmonza]

I use the urethane  bushing from Cox racing together with John Olsen springs, I like the firmer flatter ride but it would not suit everyone.

[wsamples]

I installed Wally's bushings on my silver 280SL. They work really well and improved the handling. I reused the original long 8mm bolts and all I did was run the new Nyloc nuts down until they bottomed on the threads. Easy install. Excellent results.

[wwheeler]

I think wsamples installed sway bar bushings.

I have been thinking about what James posted and the difficulty with feedback and reviews. One owner's great handling is another's too firm. All subjective. So how is a good way to approach this?

There are very few owners who had these cars new and fewer that remember what the OEM handling was like. There are those owners who have recently replaced the old bushings with OEM rubber. Most in this group are unlikely to repeat their earlier efforts and replace bushings in order to achieve better handling. The final group would be those with tired bushings. As James said, new bushings do make a difference. So do you go with OEM rubber or urethane?

Do the urethane bushings fit and install as the OEM? Absolutely. Are the current bushings the same as what Cox Racing had for several years. Absolutely. Will the urethane bushings improve the handling? Absolutely. How much? Subjective. For those looking for better handling but are concerned about a too firm of a ride, I think a stepped approach makes sense:

1) replace the sway bar bushings with urethane. Easy to do and easily reversable. Guaranteed to help handling with little effect on ride quality. Almost a no brainer to me. People have changed out to larger diameter sway bars over the years to decrease deflection. Urethane alone will decrease deflection.
2) Rear axle trailing arms. Not difficult and requires unloading the rear springs. I dislike the rear OEM rubber arm cone bushings. They seem to be wanting to extrude out and are always misaligned. Again, this job is easily reversable if it decreases ride quality beyond what the owner desires.
3) Front flat spring bushing. Harder to replace and would require a front alignment. To me, this is for the owner who wants all out handling.

Hopefully, this makes it easier to make the decision on which material to go with when replacing your W113 suspension bushings.

Wallace   

[Benz Dr.]

I did Cox bushings on the trailing arms and mounts as well as the front link pins. I this case I replaced the 19mm sway bar with a 22mm unit from a 250SE coupe. It's defiantly a firm ride.

[wwheeler]

Thing is that you don’t have to proceed all or none. Like I said, I would start with the sway bar. If you are happy then stop. If you are wanting more, then go for the rear trailing arms. If it is too much at any one point, you can always go back to OEM. There is no alteration to any of the suspension components. Plug and play if you will.